Refining process



E. V. MURPHREE Sept. 23, 1941.

REFINING PROCESS Filed Nov. 3, 1939 Ill Q; NN Mw. MN

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Patented Sept. 23, 1941 REFINING PROCESS Eger V. Murphree, Summit, N. J., assigner to Standard Oil Development Company, a corporation of Delaware Application November 3, 1939, Serial No. 302,722

(Cl. l96-96) 8 Claims.

The present invention relates to a process for the production of motor fuels. The invention is particularly concerned with a process in which petroleum oils are subjected to controlled temperature and pressure conditions in order to produce fractions of relatively higher and relatively lower boiling ranges and in which said fractions are subsequently contacted with bauin'te. In accordance with the present invention, petroleum oils are cracked in the vapor phase under total pressures in excess of '750 pounds per square inch, preferably in excess of 1500 pounds per square inch under conditions in which the partial pressure of the oil is less than about 250 pounds per square inch, preferably less than about 60 pounds per square inch. The products boiling in the motor fuel and gas oil boiling ranges are then bauxite treated under non-cracking conditions at a temperature in the range from about 600 F. to 950 F., preferably at a temperature in the range from about 800 F. to 850 F.

It is known in the art to subject petroleum oil feed stocks such as naphthas, gas oils, reduced crudes and the like to various temperature and pressure conditions for optimum time periods in order to convert said feed stocks into fractions having relatively lower and relatively higher boiling ranges. Itis also known to rene the products secured from-these cracking operations by contacting the same with clay, bauxite, sulfuric acid and the like. I have now discovered that improved unexpected results are secured if the oils are cracked in the vapor phase at total pressures in excess of '750 pounds per square inch and at oil partial pressures below about 250 pounds per square inch and then further relined by treating with bauxite. The process of my invention may be readily understood by reference to the attached drawing illustrating one modiiication of the same.

Feed oil, which for the purpose of illustration is assumed to be a gas oil boiling in the range from about 400 F. to 700 F., is introduced into primary tower I' by means of fresh feed line 2. The fresh feed oil, together with cycle oil, is withdrawn from the bottom of primary tower I by means of line 3 and introduced into heating coil 4 comprising radiant and convection sections. The oil in heating coil 4 is raised to the desired temperature and is then mixed with additional gases, preferably hot gases, which are introduced by means of line 5. The entire mixture is then further heated to the desired temperature under conditions adapted to subject the oil to a total pressure of at least 750 pounds per square inch and a partial oil pressure of not over 250 pounds per square inch. The heated oil under cracking conditions is withdrawn from heating coil 4 by means of line 6 and passed into reaction or soaking drum 'I in which the oil is maintained for an additional time period under the above mentioned cracking conditions. The oil is withdrawn from reaction drum 'I by means of line 8, passed through pressure release valve 3 and flashed into tar separator I0 from which substantially all the oil is removed overhead as a vapor by means of line II. Condensed tarry materials are withdrawn from evaporator or tar separator It by means of line I2 and removed from the system. The overhead from separator IG is introduced into primary tower I. Temperature and pressure conditions are maintained on tower I to separate a cycle oil which is recycled with the fresh feed by means of line 3 to the cracking coil and to remove overhead by means of line I3 a product of the desired endpoint. The overhead product from tower I is introduced into secondary tower I4. Temperature and pressure conditions on tower I4 are adapted to segregate a heating oil or equivalent fraction which is withdrawn by means of line I5 and handled in any manner desirable. The overhead from tower I4 having the desired endpoint, preferably in the range from about 400 F. to 420 F., comprising fractions boiling in the motor fuel boiling range and xed gases, is removed by means of line I6. The overhead iraction is preferably heated in heater I1 and then contacted with bauxite in bauxite treating plant I8. The bauxite treated oil is withdrawn from bauxite treating unit I8 by means of line I 9, preferably contacted with clay in clay contacting plant 2l, cooled in condenser 20 and then passed into distillate drum 2l. Uncondensed gases are withdrawn from distillate drum 2l by means of line 22, heated in heating coil 23 and recycled as described by means of line 5. A portion of the gases is also preferably recycled to the bauxite treating unit I8 with the overhead removed from tower I4 by means of 1in-e 24. Excess gases are removed from the system by means of line 25. The condensed distillate is removed from distillate drum 2| by means of line 26 and handled in any manner desirable. It is to be understood that under certain conditions the overhead from tower I4 may be condensed in condenser 28 and passed to distillate drum 29. The uncondensed gases from distillate drum 29 are removed by means of line 30 and recycled through heating coil 23 as described. The condensed dis- Vtillate is Withdrawn by means of line 3|, passed through heating coil Il and into bauxite treating unit I8. Gases produced in bauxite treating unit I8 are separated in Vdistillate drum 2l and preferably recycled by means of line 24. The desired operation may readily be secured by adjusting valves 42, 32, 3S, Sii, 35, 30, 31, 38, 39. and 40.

The process of the present invention may be Widely varied. In general, the process isV directed to bauxite treating petroleum oils cracked in the vapor phase at a total pressure in excess of 750 pounds per square inch, preferably in excess of 1500 pounds per square inch, and under a partial pressure of less than 250 pounds per square inch, Y

preferably less than 60fpounds per square inch. Cracking temperatures are in the range above 1000 F., preferably in the range from about.

1000 F. to 1100 F. These oils boiling generally in the motor fuel boiling range are bauxite treat- Ied under substantially non-cracking conditions at a temperature in the range above 600 F., preferably in the range above 800 F. The pres- Y' sure employed in the bauxite treating stage may likewise vary considerably. However, it is desirable to `employ elevated pressures in the range 1from about `200 pounds per square inch to about 400 pounds per square inch. Under these conditions it may .be possible to reduce or eliminate the clay treating stage. The bauxite treated oil may be clay contacted under widely diierent temperatur-e and pressure conditions.' In general, it is preferred to clay contact the oil at temperatures in the range from 500 F. to 550 F. p The amountof gases recycled from distillate drum 2l to heating coil vi is suiiicient to secure fthe desired relationship of total to partial pressure. This relationship may be secured by introducing extraneous suitable gases into the system by means `of -line fil, as for example, steam, propane, butane, or the like. Although additional heating is required, a preferred modification of the present invention is to condense the overhead from `Ithe secondary tower and to recycle uncon- -densed vapors from the distillate drum to the heating coil.y vThe substantially gas free distillate is then heated to bauxite treating conditions. If desired, it may be combined with gas evolved in the bauxite treating stage which is recycled from .the distillate drum following either the bauxit .or clay treatment. A

The process of thepresent invention is not toY belimited by any theory or Inode of operation,

' but only in and by the following claims in which .it is desired to claim all novelty in so far as the prior art permits. I claim:

1l. Process for the production of motor fuels comprising cracking a petroleum oil under a total *pressure in the range above about '750 pounds per square inch and under an oil partial pressure Lof less than about 250 pounds per square inch,

.separating the cracked product boiling inthe motor .ffuel boiling range and contacting-the same -.with bauxite under substantially non-cracking conditions at a temperature in the range above 2. Process in accordance with claim 1 in which said oil is contacted with bauxite at a temperature in the range above 800 F.

partial pressure of less than 60 pounds per squareV inch, separating the cracked products boiling in the motor fuel boiling range, contacting this fraction with bauxite under non-cracking conditions at a temperature in the range above about 600 F.

4. Process in accordance with claim 3 in which said oil is contacted with bauxite at a temperature in the range above about 800 F.

5. Process for the production of high quality motor fuels comprising cracking a petroleum oil in the vapor phase at a total pressure in the range above about '750 pounds per square inch gauge and at -an -o-il partial pressure of less than about 250 pounds per square inch gauge, separating the cracked product boiling in the range below 420 F., contacting ysaid fraction with bauxite Yat a temperature in the range above about 600 F., cooling the bauxite treated material to condense the fractions boiling in the motor fuel boilingrange and separating :the normally gaseous hydrocarbons therefrom, recycling :said normally gaseous hydrocarbons to said cracking opera-tion 'in order to secure said ltotal pressure and said oil partial pressure.

6. Process i-n accordance with claim 5 in which the total pressure is in the range above about 15.00 pounds per square inch and the oil partial pressurev is in the range below about 60 pounds per square inch and in which said oil is contacted with bauxite at a temperature in the range above about 800 F.

7. Process for the production of high quality vmotor fuels comprising cracking a petroleum oil :in the vapor phase at a total pressure in excess of '.750 pounds per square inch and at an oil partial pressure of less than about 250 pounds per `square inch, separating cracked products boiling the range below about 450 F., cooling said 8. Process in accordance with claim 7 in which f the total pressure is in excess of about 1500 pounds per square inch and in Which the partial pressure of the oil is less than about 60 pounds per square inch and in which the oil is contacted with bauxite at a temperature in the range abovev about 800 F.

EGER V. 

